Over a period of four years, longitudinal data have been collected for a rural population. In 1975, similar data were collected for an urban population. The purpose of the research is two-fold; First, the longitudinal study is being conducted to evaluate the impact of an innovative primary health care delivery program on the population served. To measure impact, a health status index based on health-related behavior of individuals is being used. The research design includes both random samples and panels and a control population. Second, and concurrent with the evaluation discussed above, several health indexes thought to have promise are being validated and compared. This research is scheduled to be completed in June 1977 and is being funded by the National Center for Health Services Research, Public Health Service, Department of Health, Education and Welfare.